Logmon and Microsoft IIS FTP logfile

I have to parse Logfile to find a specific string and genrerate an alarm...

A new logfile is created every week and its name is formated like YYMMWW.log wher YY is the last 2 digits of the actual year, MM is the last 2 digits of the actual month and WW is the last 2 digits of the actual "month week"

How could I configure the logmon probe to check the last log file on its name or on its last modification date?

I do not think you can specify "week of month" in the logmon probe. The rest is definitely feasible. The help file for the logmon probe has the full list of time-formatting primitives you can use when entering the filename.

You can configure the logmon probe to expect a certain word/line in the log file. The Match on every run option is under the Advanced tab within a watcher rule. It causes the watcher to generate an alarm when it does not match any lines during a scan of the file.